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A method for the accurate determination of crystal truncation rod intensities by X‐ray diffraction
Author(s) -
Specht E. D.,
Walker F. J.
Publication year - 1993
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889892011592
Subject(s) - diffraction , momentum transfer , optics , specular reflection , physics , diffractometer , perpendicular , beam (structure) , detector , diffraction topography , scattering , crystal (programming language) , x ray crystallography , geometry , mathematics , scanning electron microscope , computer science , programming language
A method is described for determining the structure factor F ( Q ) at a scattering vector Q along a crystal truncation rod (CTR) by measuring the total power diffracted with the crystal fixed. When a detector collects the entire diffracted beam, P CTR / P 0 = pσT [λ| F ( Q )|/ a 0 sin θ sin χ] 2 , where P 0 and P CTR are the powers of the incident and diffracted beams, p is a polarization factor, σ T is the Thompson cross section, λ is the X‐ray wavelength, a 0 is the area of a two‐dimensional unit cell and θ and χ are diffractometer angles. No terms due to instrumental resolution are required for measurement of the structure factor. Simple expressions are derived relating structure factors to the integrated intensity of rocking curves employing a receiving slit wide enough to accept the diffracted beam in one direction only. Measurements employing a narrow slit are useful in measuring CTR intensity at grazing incidence ( i.e. small perpendicular momentum transfer) or for specular reflection ( i.e. small parallel momentum transfer). For the more general case (large perpendicular and parallel momentum transfer), accurate measurements are more easily made when the detector collects the entire diffracted beam